Free-chain hoist



sept. 1s, 1934. F W, OFFING 1,973,844

FREE CHAIN HOIST Filed D60. 9, 1933 INVENTOR.

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@M4/gam?) ATTORNEYS.

Patented Sept. 18,V 1934 UNITED STATES FREE-CHAIN HOIST -Fredrick W. Ceiling, Danville, Ill.`

Application December 9, 1933, Serial No. 701,651

10 Claims.

This invention relates to a free-chain hoist and by free-chain hoist is meant a hoist which is capable of having the load supporting chain rapidly positioned to an approximate position for 5 associating the load therewith as distinguished from a hoist wherein the load supporting chain must through the operation of the device, be positioned relative to a load by performing the same operation for lowering the chain to the desired position for load engagement, as is required to raise it for elevating the load.

The chief difficulty encountered in a free-chain hoist is not in providing for the rapid movement of the chain when not under load corresponding l to the movement of the chain for'load elevation but it is the repositioning of the chain to the desired position for load engagement when the chain has to be lowered whether under load or not, and this invention is particularly directed to the solution of that dimculty. Free-chain hoists have been perfected having these desideratums and I have obtained several patents thereon. The present invention is directed to another solution of this broad problem.

The chief feature of the invention consists in providing a free-chain hoist with mechanism which includes a brake construction, a clutch construction, a power construction, associated with which is the clutch construction and the sprocket engagement by the chain, and an arrangement whereby a portion of the power construction is disassociated from the remainder of the power construction to permit relatively free sprocket movement but only after the load has been relieved from the sprocket, thereby preventing dropping of the load and thus permitting free-chain movement for reverse positioning of the chain.

The full nature of the invention will be under- 40 stood from the accompanying drawing and the following description and claims:-

In the drawing, Fig. 1 is a sideelevational view of one embodiment of the invention, including a ratchet and dog, constituting an embodiment of a one-way clutch construction, the cover of the hoist being removed to illustrate in elevation more clearly the invention.

Fig. 2 is a sectional view through the hoist shown in Fig. 1, certain parts, however, being shown in elevation.

Fig. 3 is a view taken at right angles to Fig. 1, vthe cover being removed and of the gear shifting and brake releasing mechanism, and in the brake engaging and gear engaging position.

Fig. 4 is a view similar to Fig. 3 of the same (ol.- '2M-171) parts in the brake releasing and the gear nonmeshing position.

In the drawing 10 indicates a housing provided with a cover 11 suitably secured together by screw bolts associated with the lugs or ears 12 formed upon both housing and cover. The housing and cover jointly form a bearing 13 for the hook 14 by which the hoist may be sustained or suitably supported. The housing is provided with a cutout portion 15 which provides both an entrance 65 and exit for a sprocket chain 16 that may be provided at one end with a stop 17. Stop 17 is adapted to engage ange 18 of the cover 11 and thus prevent the chain from jumping off the sprocket. The sprocket chain 16 includes any 70 suitable form of load attaching member, such as .a screw eye 19, for association with a weight or load 20. As shown in some of the patents I have previously referred to, the screw eye 19 may and preferably does consist of a hook or the like.

The cover at 21, see Fig. 2, and the housing at 22 provide bearings for a shaft 23 which mounts a sprocket 24 that may, if desired, be formed integral with said shaft. Suitably and rigidly secured to the shaft is a gear 25. 'I'he cover is provided with a bearing 26 and the housing is provided with a bearing 27, the latter being closed and the former consisting of an opening through the cover. Mounted in-these bearings areI the anti-friction constructions 28 and 29 respectively.

Rotatably supported by said anti-friction constructions, is a shaft 30, one end of which is fully enclosed by the housing and the other end 3l of which projects beyond the hoist and herein the cover portion, and is provided with suitable power means for rotating the shaft in either direction. Herein the exposed end 31 of shaft 30 is shown provided with a wheel 32 rigidly secured to said shaft and the same carries an endless chain 33 of the transverse link type.

A suitable guide, or retainer, in the form of a U-shaped bracket 34 with the cover with which it is integral, envelopes the wheel 32 and serves to prevent escapement of the chain 33 from the wheel. Any suitablel means for securing the wheel 32 to the shaft may be provided, the same not being shown herein. The shaft 30 includes a collar 35 against which bears one end of the spring 36 concentric with the shaft and telescopically mounted upon a tubular extension 37 of a pinion 38 that is slidably ymounted on said shaft and is adapted to be rotated by said shaft through suitable means, such as a spline connection 39. The. pinion 38 normally meshes with the gear 25, but is removable therefrom.

PATENT ori-ice It will thus be apparent that when the shaft 31 is rotated in either direction, the sprocket will be rotated in a corresponding direction for load elevation or load lowering, if the pinion 38 is in meshing engagement with the gear 25. If the pinion is not engaged with the gear, then the chain 33, or other power means, is not effective, no matter how much rotated for obtaining sprocket movement. By reason of the possibility of disassociating the pinion and gear, means must be provided for holding the sprocket corresponding to the desired position the load is to be held in to permit working on the load. Such means, herein, includes a brake drum 40, see Fig. 1, and a brake band 42 which has one end suitably anchored to the housing and which has its other end extended as at 43. Supported thereby adjacent the end 43 is an angular arm 44 that mounts one end of a coil spring 45, the other end of which is secured to an arm 46, pivotally mounted as at 47 in an opening in the housing 10.

'I'he exposed end of member 47 is provided with suitable means 48, whereby from without the housing the position of the arm 46 may be clampingly associated with the housing to determine the fixed position of the arm 46. When the arm is positioned as shown in Fig. 1 the coil spring is under what may be termed normal tension. When the arm 46 is rotated into a lowered position an additional tension will be imposed upon the coil spring 45. This brake band 42, therefore, is always constrained by said spring 45 into drum engagement. The band, if desired, may be provided with a facing 49, as is well understood in the brake art. This brake structure is adapted to hold the sprocket and load in the desired position.

Inasmuch as the brake is normally constrained toward braking operation at all times, it will be apparent that it is highly desirable that the brake structure in the load elevating movement, be relatively inoperative, and to accomplish this purpose there is provided an overrunning clutch in the form of a, ratchet 50 which is suitably secured to the shaft 30 as at 51 and the teeth 52 thereof are engaged by a plurality of diametrically positioned dogs 53 normally urged into ratchetengagement by springs 54 supported as at 55 upon the brake drum structure. 'Ihe dogs 53 are pivotally supported'as at 56 upon the brake drum structure.

`With this type of construction, the brake drum, it will be apparent-see Fig. 2-is normally stationary and shaft 30 is freely rotatable in the drum 40 for load elevation. Thus as shaft 30 is rotated to actuate the two meshing gears to turn the sprocket 24 to elevate the load 20, the ratchet revolves clockwise in Fig. 1 and the pawls or dogs 53 ride over the teeth of the ratchet and set between the teeth, so that when the rotational movement is discontinued, the dogs engage the Ateeth and thus immediately connect the brake drum to the shaft 30 and through the pinion 38 serve to lock the sprocket wheel 24 in that position and the load will be held elevated by the brake until such time as the force of spring 45 isopposed.

'Ihe means for releasing the brake `and to the desired degree, to permit the load to be lowered at the desired rate, consists of a lever 60 pivoted at 61 tothe housing and said lever has one arm 62 engaged with the end 43 of the brake band 42. The opposite end of the lever 60 is provided with an opening 64 that receives a hook 65 that terminates in a rod 66 that passes downwardly through the opening 67 in the housing 10 and terminates in the eye 68, to which may be attached a control cable 69. When the cable 69 is pulled downwardly, the lever 60 is rocked on its pivot 61 and the same causes the brake band 42 to move upwardly in the housing in opposition to the downward tendency imposed by the spring 45, and this serves to release the drum from band engagement, thereby permitting the Adrum together with the shaft, the meshing gears and the sprocket to reversely rotate to permit lowering of the load due to the weight of the load. The rate of lowering may be determined by the amount of pull exerted on the cable 69 or in other words, the amount of tilting movement imparted to the lever 60.

'I'he construction so far described, is not of a free chain character. The advantages of a freechain hoist are too numerous to mention, but have been suggested herein before. Briefiy, a so-called free-chain hoist permits the rapid positioning of the chain in a position adjacent to the load for connection to the load and with a relative freedom of movement, as distinguished from the progressive movement of the chain when under load during the lowering and/or the raising thereof.

The means herein provided for free-chain action consists in a means for removing the pinion from meshing engagement with the gear. It is perfectly evident, however, that when this type of disconnection is provided in the source of power applied to the sprocket and inasmuch as the brake construction also is effective on the sprocket only through said meshing engagement, it will be evident that some means must be provided to prevent disengagement of the gears until the weight of the load has been taken oif the chain.

'Ihe means forfsecuring non-meshing engagement of the pinion 38 with the gear 25, includes a yoke member 71 having the arms 70 that straddle the shaft 30 and having one face bearing against the opposite end of the pinion 38, it being remembered that the other end is associated with the spring 36 that normally constrains the pinion 38 into normal meshing engagement with the gear 25. The yoke member 71 is pivotally supported at 72 upon a bracket 73 suitably secured to the housing as at 74. The other end of the lever 71 or yoke shifter, and herein indicated by the numeral 75, terminates adjacent one arm 76 of a bell crank lever pivoted at 77, to the housing and herein pivot 77 is coaxial with the mounting 74. The other arm 78 of the bell crank lever, see Figs. 3 and 4, is connected to one end 79 of the spring 80, said spring having a hook 81 at its opposite end that is associated with a slot 82 in the end of lever 60.

Normally, as stated, spring 36 tends to'maintain the pinion and gear in meshing engagement. Normally, as stated, spring 45 tends to maintain the brake band in braking engagement with the drum. In so doingit tends to tilt the lever 60 counter clockwisesee Fig. l-and this serves to relieve the tension interposed between the lever 60 and the bell crank'lever 76 upon the spring 80. In this connection, -it will be apparent the yoke shifter 71 is relatively'freel floating and that when actuated, as before mentioned, it is only effective for moving the pinion out of meshing engagement in opposition to spring 36.

Initial application of power in the form of a manual pull upon the cable 69 serves to tilt lever 60 clockwise upon pivot 61 which releases the brake drum from band engagement and permits the sprocket to revolve in a reverse direction due to the weight of the load for lowering the load, the rate of said lowering being'determined by the veffective on the chain for rotating the sprocket reversely for load lowering, there is sufficient frictional load as well as contact load between the two gears, that is, the pinion and the larger gear, so that the yoke shifter cannot shift the pinion out of engagement from the larger gear. As soon as the load has been deposited upon a suitable support and thus is in its lowered position, vthe weight of the load is removed from the chain. Then continued pulling of the cable 69 will free the brake drum simultaneously with the actuation or tilting of the yoke shifting lever to secure disengagement of the pinion from the gear 25. When it is accomplished, the sprocket and the gear together with the chain may be freely actuated for adiusting the chain as desired.

When the load engaging member 19 is positioned approximately at the point desired for load engagement, the cable 69 is released, whereupon the pinion, dueto the spring 36 which opposes spring 80, reengages with the gear 25 and at the same time spring 45, due to the removal of the opposing force transmitted through the lever 60 again causes the brake band to engage the drum to normally hold the drum against rotation in the application of rotational power to the sprocket for load elevation.

While the invention has been described in great detail in the foregoing specification, the same is to be considered as illustrative and not restrictive in character. Various modifications, such as a different type of brake construction or a different type of clutch construction or a diiferent type of overrunning clutch construction, as well as a different type of gear shifting mechanism, together with others of equivalent character which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of this invention, reference being had to the appended claims.

The invention claimedY isry 1. In a free-chain hoist, the combination with a chain engaging sprocket, a housing, a shaft therein having an exposed operating end, and means on said shaft for rotating the same, of a reducing gear structure between the shaft and sprocket. and including a pair of meshing gears, one of said gears being movable into and out of meshing engagement. a brake construction, means normally constraining said construction to inoperative relation during load elevating movement, means for rendering said brake construction operative when the load is stationary and other means for releasing said brake construction for load lowering until the weight of the load is relieved from said sprocket, said means being then operative for moving one of the gears out of meshing engagement to permit free reverse rotation of the sprocket for free-chain movement.

2. In a free-chain hoist, the combination with a chain engaging sprocket, a housing, a shaft therein having an exposed operating end, and means on said shaft for rotating the same, of

However, all` erative when the load is stationary, and other means for releasing said brake construction for load lowering until the weight of the load is relieved from said sprocket, said means .being then operative for moving Vone of the gears out of meshing engagement to lpermit free reverse rotation of the sprocket for free-chain movement, said brake construction including an overrunning clutch permitting free rotation of the sprocket relative to the brake for load elevation and preventing reverse rotation of the sprocket when subjected to load to prevent load lowering.

3. In a free-chain hoist, the combination with a chain engaging sprocket, a housing, a shaft therein having an exposed operating end, and means on said shaft for rotatingl the same, of a reducing gear structure between the shaft and sprocket and including a pair of meshing gears, one of said gears being movable into and out of meshing engagement, a brake construction, means normally constraining said construction to inoperative relation during load elevating movement, means for rendering said brake construction operative when the load is stationary, and other means for releasing said brake construction forload lowering until the weight of the load is relieved from said sprocket, said means being' then operative for moving one of the gears out of meshing engagement to permit free reverse rotation of the sprocket for free-chain movement, said brake construction including an overrunning clutch permitting free rotation of the sprocket relative to the brake for load elevation and preventing reverse rotation of the sprocket when subjected to load to prevent load lowering, the said other means for releasing the brake construction permitting the lowering of the load at the desired rate corresponding to the degree of release of the brake construction.

4. A combination clutch and brake construction for a free-chain hoist, and the like, including a brake band, a brake drum normally engaged thereby, a ratchet, dog means carried by the drum permitting overrunning of the ratchet relative to the drum, a gear, a rotatable shaft, another gear meshing with said first meshing gear and movable on and rotatable by said shaft, said ratchet being rotatable by said shaft, and means for initially releasing said band and constraining said movable gear into non-meshing position and subsequently moving said movable gear into nonmeshing position when the friction of the load between the gears is substantially reduced to minimum contact friction.

,5. A combination clutch and brake construction for a free-chain hoist, and the like, including a brake band, a brake drum normally engaged thereby, a ratchet, dog means carried by the drum permitting overrunning of the ratchet relative to the drum, a gear, a rotatable shaft, another gear meshing' with said first mentioned gear and movable on and rotatable by said shaft, said ratchet being rotatable by said shaft, and means for initially releasing said band and constraining said movable gear into non-meshing position and subsequently moving said movable gear into non-meshing position when the friction of the load between the gears is substantially reduced to minimum contact friction, said last mentioned means including a springnormally urging the band into drum engagement and a gear shifter, -a manually operable member operatively associated with the band for releasing the same to the desired degree in opposition to said spring and operatively associated with said shifter for constraining the same for shifting operation.

6. A combination clutch and brake construction for a free-chain hoist, and the like, including a .brake band, a brake drum normally engaged thereby, a ratchet, dog means carried by the drum permitting overrunning of the ratchet relative to the drum, a gear, a rotatable shaft, an-

ated with the band for releasing the same tothe desired degree in opposition to said spring and operatively associated with said `shifter for constraining the same for shifting operation, the operative association between the shifter and the manually operable means including a spring normally extensible by the manually operable means for normally constraining the shifter for shifting operation.

'1. A combination clutch and brake construction for a free-chain hoist, and the like, including a brake band, a brake drum normally engaged thereby, a ratchet, a dog means carried by the drum permitting overrunning of the ratchet rel-` ative to the drum, a gear, a rotatable shaft, another gear meshing with said rst mentioned gear and movable on and rotatable by said shaft, said ratchet being rotatable by said shaft, means for initially releasing said band and constraining said movable gear into non-meshing position and subsequently moving said movable gear into non# meshing position when the friction of the load between the gears is substantially reduced to minimum contact friction, said last mentioned means including a spring normally urging the band into drum engagement` and a gear shifter, a manually operable member operatively associated with the band for releasing the same to the desired degree in opposition to said spring and operatively associated with said shifter for constraining the same for shifting operation, and means for manually adjusting the force of the spring normally urging the band into drum engagement.

8. A combination clutch and brake construction for a free-chain hoist, and the like, including a brake band, a brake drum normally engaged thereby, a ratchet, dog means carried by the drum permitting overrunning of the ratchet relative to the drum, a gear, a rotatable shaft, another gear meshing with said iirst..mentioned gear and movable on and rotatable by said shaft,

said ratchet being rotatable by said shaft, means for initially releasing said band and constraining said movable gear into non-meshing position and subsequently moving said movable gear into nonme'shing position when vthe friction of the load between the gears is substantially reduced to minimum contact friction, said last mentioned means including a spring normally urging the band into drum-engagement and a gear shifter, a manually operable member operatively associated with the band for releasing the same to the desired degree in opposition to said spring andl operatively associated with said shifter for constraining the same for shifting operation, the operative association between the shifter and the manually operable means including a spring normally extensible by the manually operable means for normally constraining the shifter for shifting operation, and means for manually adjusting the force of the spring normally urging the band into drum engagement.

9. In a free-chain hoist, the combination of a chain engaging sprocket, a shaft, means for rotating the shaft, a meshing gear structure including a pair of gears, one of said gears being operatively connected with the sprocket, the other gear having a slidable connection with said shaft for movement into and out of meshing engagement, a brake structure, a one-way clutch between the brake structure and the shaft, means normally constraining the brake structure to brake operation for restricting free shaft rotation, means normally constraining the other gear toward meshing engagement, other means for moving the slidable gear out of gear engagement in opposition to said last mentioned constraining means, a single control member for releasing said brake structure and disengaging said gears, means operatively connectinglthe brake structure and gear moving means to said member whereby brake actuation occurs previous to gear disengagement, said means including a yielding member between thesingle control member and the gear sliding means, initially expansible upon control member operation to permit brake release without gear disengagement.

10. In a free-chain hoist, the combination with a load sustaining chain engaging sprocket, an operating shaft, .and means on said shaft for rotating the same, comprising a wheel and chain of considerable mass, of a meshing gear structure interposed between the shaft and sprocket, one of said gears being movable into and out of gear meshing engagement, a brake construction normally constrained to prevent free rotation of the shaft in load lowering direction, a one-way clutch between said brake structure and said shaft and arranged to permit free rotation of -said shaft in the load elevating direction, means for moving the moving gear into andI out of meshing engagement, and means operatively connected to the brake structure and the gear disengaging means arranged to initially release 

